package nineteen type Nineteen struct { mapping mapping } func Init(filepath string) *Nineteen { nineteen := &Nineteen{ mapping: mapping{}, } nineteen.mapping.load(filepath) return nineteen } func (d *Nineteen) Answer() string { return "nineteen part 1 answer for mapping" } func (d *Nineteen) FollowUp() string { return "nineteen part 2 answer for mapping" }